JP2004214624A - Plasma processing apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a plasma processing apparatus, for less frequency in replacement of a sticking preventing member. <P>SOLUTION: In the plasma processing apparatus, provided with a plasma chamber for generating plasma through electronic cyclotron resonance and a sample chamber for holding a sample processed by the plasma, an sticking-preventing tube 2 for preventing a product material by the plasma from sticking to the inner wall of the plasma chamber is separated into a plurality of partial sticking preventing tubes 21, 22, 23 depending on the temperature distribution at generation of the plasma. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

  The present invention relates to a plasma processing apparatus that performs processing such as thin film formation using plasma, and more particularly to a deposition prevention technique for preventing silicon oxide or the like from adhering inside the plasma processing apparatus.

2. Description of the Related Art In recent years, in manufacturing electronic devices such as semiconductor integrated circuits, sputtering and etching have been performed using high-energy plasma obtained by electron cyclotron resonance (ECR).
For example, in the ECR sputtering method, one or more types of gas (for example, argon gas) are decomposed by plasma whose energy is increased by electron cyclotron resonance, and the generated ions collide with a target. With this collision, molecules generated by a reaction between the metal atoms jumping out of the target or the metal atoms jumping out of the target and the gas in the deposition chamber are deposited on the sample.

FIG. 6 is a cross-sectional view illustrating the configuration of an ECR sputtering apparatus used for the ECR sputtering method. As shown in FIG. 6, the ECR sputtering apparatus 6 includes a film forming chamber 601 and a plasma chamber 607, which are adjacent to each other. A sample stage 604 is provided in the film forming chamber 601, and a sample 603 is set on the sample stage 604.
A plasma inlet 606 communicating with the plasma chamber 607 is provided on the plasma chamber 607 side of the sample 603 in the film formation chamber 601. A ring-shaped metal target 605 is provided so as to surround the plasma introduction port 606. The metal target 605 is made of a solid material containing silicon or the like, and is a material of a film formed on the sample 603.

Microwave 608 is introduced into plasma chamber 607 via waveguide 609. A microwave introduction window 610 is provided between the plasma chamber 607 and the waveguide 609. The microwave introduction window 610 is made of quartz glass, and seals the opening of the plasma chamber 607 provided on the waveguide 609 side to keep the plasma chamber 607 airtight.
Further, an exhaust port 602 is provided in the film forming chamber 601. The gas inside the film forming chamber 601 and the plasma chamber 607 is exhausted from an exhaust port 602 by a vacuum device (not shown). In this manner, when the inside of the film forming chamber 601 and the plasma chamber 607 is evacuated, a plasma forming gas such as argon is introduced from the gas inlet 611 provided in the plasma chamber 607. You.

An excitation coil 612 is provided around the plasma chamber 607. When a gas is introduced into the plasma chamber 607, the exciting coil 612 forms a magnetic field in the plasma chamber 607 and generates a discharge by electron cyclotron resonance. Then, high-density plasma is generated, and argon ions are generated.
The generated argon ions are drawn from the plasma chamber 607 to the film formation chamber 601 via the plasma inlet 606.

  A negative potential is applied to the metal target 605. The argon ion collides with the metal target 605 by the action of the electric field generated by the negative potential. Thus, silicon atoms fly out of the metal target 605 and deposit on the sample 603. In addition, molecules generated by a reaction between the silicon atoms jumping out of the metal target 605 and the gas in the deposition chamber 601 are deposited on the sample 603.

Thus, a film is formed on the sample 603 (see, for example, Patent Document 1).
JP-A-1-306558 (from page 2 to page 4 and FIG. 1)

Now, when forming a film on the sample 603, the silicon atoms jumping out of the metal target 605 not only deposit on the sample 603 but also adhere to the inner wall of the ECR sputtering apparatus such as the inner wall of the plasma chamber 607. I do. In order to prevent such adhesion, deposition plates 613 and 614 and deposition tubes 620 are provided inside the plasma chamber 607.
The deposition prevention tube 620 is a cylindrical quartz tube. The deposition-preventing plate 613 is made of a disc-shaped quartz plate having a round hole made of a round hole, and the deposition-preventing plate 614 is made of a disc-shaped quartz plate having a square hole made of a square hole. . Accordingly, the silicon atoms adhere to the deposition-proof tube 620 and the like, and do not adhere to the inner wall of the plasma chamber 607. That is, when the film forming process is repeated in the ECR sputtering apparatus, a film made of silicon oxide or the like adheres and grows on the deposition-proof tube 620 or the like.

On the other hand, when plasma is generated, inside the plasma chamber 607, the temperature is high at the central portion, and the temperature decreases as approaching the peripheral portion. Therefore, the temperature of the deposition prevention tube 620 becomes higher as it is closer to the central portion of the plasma chamber 607, and the temperature becomes lower as it is closer to the peripheral portion. Therefore, thermal stress is generated inside the deposition prevention tube 620 due to this temperature difference. I do.
For this reason, if the film forming process is repeated in the ECR sputtering device, the anti-adhesion tube 620 is damaged by thermal fatigue. As a result, fragments such as silicon oxide adhered and grown on the deposition prevention tube 520 and fragments of the deposition prevention tube 620 themselves are scattered to hinder the movement of argon ions. Film formation characteristics cannot be obtained.

As a countermeasure against such a problem, if the deposition tube 620 is replaced, necessary film forming characteristics can be recovered. However, since the deposition chamber 601 must be opened to the atmosphere in order to replace the deposition-proof tube 620, after the operation, an operation such as evacuation of the deposition chamber and removal of water is required.
This evacuation and water removal require a great deal of work time. Further, if the attachment tube 620 is frequently replaced, the necessity of the attachment tube 620 itself increases, which is not preferable from the viewpoint of cost. Such a problem exists not only in an ECR sputtering apparatus, but also in an ECR etching apparatus and other plasma processing apparatuses using electron cyclone resonance, and also in a general plasma processing apparatus that generates high-density plasma and uses it.

This is because the temperature difference in the plasma chamber is generated even if another method is used, and the higher the density of the generated plasma, the higher the temperature, and the temperature difference further increases.
For example, when the plasma density is about 10 ¹¹ ions / cm ³ , the plasma temperature is estimated to be 600 ° C. or higher. At such a high temperature, the thermal influence on the deposition-proof tube becomes large.

  The present invention has been made in view of the above-described problems, and has as its object to provide a plasma processing apparatus that can reduce the frequency of replacing a deposition-inhibiting member.

  In order to achieve the above object, a plasma processing apparatus according to the present invention includes a plasma chamber that generates high-density plasma, a sample chamber that communicates with the plasma chamber, and that holds a sample to be processed by the plasma. A deposition tube for preventing products generated by the plasma processing from adhering to the inner wall of the plasma chamber, wherein the deposition tube is divided into a plurality of pieces according to a temperature distribution at the time of the plasma generation. It is characterized by the following.

By doing so, the thermal stress generated due to the temperature difference between the parts of the deposition-preventing pipe during the plasma processing can be released, so that damage to the deposition-preventing pipe can be prevented. Therefore, the replacement frequency of the deposition-inhibiting member can be reduced, and the running cost of the plasma processing apparatus can be reduced.
Further, in the plasma processing apparatus according to the present invention, the plasma chamber has a cylindrical shape, the deposition-preventing tube has a cylindrical shape, is inserted into the plasma chamber, and is divided in the tube axis direction. It is characterized by having. By doing so, the concentration of stress can be prevented, so that the deposition prevention tube can be made harder to break.

Further, in the plasma processing apparatus according to the present invention, the deposition prevention tube is divided such that a portion having a larger temperature gradient during the plasma generation has a smaller tube length, and a portion having a smaller temperature gradient has a larger tube length. It is characterized by having.
In this way, for each of the plurality of partial deposition tubes constituting the deposition tube, the temperature difference within one partial deposition tube can be reduced to suppress the generation of thermal stress. Therefore, it is possible to prevent the partial protection tube from being damaged, and thus to prevent the entire protection tube from being damaged.

Further, the plasma processing apparatus according to the present invention is characterized in that a groove parallel to the tube axis is provided on an inner wall surface of the deposition-proof tube. By doing so, the strain caused by the stress caused by the film adhering to the inside of the deposition prevention tube can be released, and the distortion of quartz caused by the stress can be released more efficiently. Therefore, it is possible to prevent the attachment tube from being damaged.
Further, in the plasma processing apparatus according to the present invention, the deposition tube is provided with a plurality of grooves, and the plurality of grooves are provided at equal intervals around a pipe axis of the deposition tube. Features.

This makes it possible to disperse the stress caused by the expansion of the adhered film, thereby preventing damage to the deposition prevention tube. In this case, it is preferable that the longitudinal direction of the groove provided on the inner wall of the protection tube is perpendicular to the direction of the stress on the protection tube by the adhesion film. With this configuration, the stress can be efficiently released.
Further, the plasma processing apparatus according to the present invention is characterized in that the deposition prevention tube is made of quartz. By doing so, it is possible to withstand high temperatures at the time of plasma generation and prevent unnecessary substances from adhering to the inner wall of the plasma chamber. In addition, the deposition prevention tube itself can be hardly damaged.

The plasma processing apparatus according to the present invention is characterized in that the sample is subjected to a sputtering process using the plasma. In this case, the deposition prevention tube installed in the sputtering apparatus can be hardly damaged. Therefore, the production efficiency by the sputtering device can be improved.
Further, a plasma processing apparatus according to the present invention includes a plasma chamber that generates high-density plasma, a sample chamber that is in communication with the plasma chamber, and that holds a sample to be processed by the plasma, A deposition tube for preventing the product from adhering to the inner wall of the sample chamber, wherein the deposition tube is divided into a plurality according to the temperature distribution at the time of the plasma generation. .

With this configuration, in the deposition-preventing tube that prevents the deposition tube from adhering to the inner wall of the sample chamber, thermal stress corresponding to the temperature gradient generated during the plasma processing can be released, thereby preventing damage to the deposition-preventing tube. be able to. Therefore, the running cost of the plasma processing apparatus can be reduced.
Further, in the plasma processing apparatus according to the present invention, the sample chamber has a cylindrical shape, the protection tube has a cylindrical shape, is inserted into the sample chamber, and is divided in the tube axis direction. It is characterized by having. In this way, it is possible to prevent the concentration of thermal stress in the deposition-preventing tube, and to further prevent the deposition-preventing tube from being damaged.

Further, in the plasma processing apparatus according to the present invention, the deposition prevention tube is divided such that a portion having a larger temperature gradient during the plasma generation has a smaller tube length, and a portion having a smaller temperature gradient has a larger tube length. It is characterized by having.
In this way, for each of the plurality of partial deposition tubes constituting the deposition tube, the temperature difference within one partial deposition tube can be reduced to suppress the generation of thermal stress. Therefore, it is possible to prevent the partial protection tube from being damaged, and thus to prevent the entire protection tube from being damaged.

Further, the plasma processing apparatus according to the present invention is characterized in that a groove parallel to the tube axis is provided on an inner wall surface of the deposition-proof tube. In this way, the strain caused by the stress caused by the film adhering to the inside of the deposition prevention tube can be released, and the distortion of quartz caused by the stress can be released more efficiently. Therefore, it is possible to prevent the attachment tube from being damaged.
Further, in the plasma processing apparatus according to the present invention, the deposition tube is provided with a plurality of grooves, and the plurality of grooves are provided at equal intervals around a pipe axis of the deposition tube. Features.

According to this configuration, the stress generated by the expansion of the adhesion film can be dispersed, so that damage to the deposition prevention tube can be prevented. Also in this case, as described above, it is preferable that the longitudinal direction of the groove provided on the inner wall of the deposition-preventing pipe is orthogonal to the direction of the stress on the deposition-preventing pipe due to the adhesion film.
Further, the plasma processing apparatus according to the present invention is characterized in that the deposition prevention tube is made of quartz. With this configuration, it is possible to withstand high temperatures during plasma generation and prevent unnecessary substances from adhering to the inner wall of the plasma chamber. In addition, the deposition prevention tube itself can be hardly damaged.

Further, the plasma processing apparatus according to the present invention is characterized in that the sample is subjected to an etching process using the plasma. By doing so, it is possible to make it difficult for the deposition-proof tube installed in the etching apparatus to be damaged. Therefore, the production efficiency of the etching apparatus can be improved.
The plasma processing apparatus according to the present invention is characterized in that the sample is subjected to a CVD process using the plasma. By doing so, it is possible to make it difficult to damage the deposition-proof tube installed in the plasma CVD apparatus. Therefore, it is possible to extend the cycle of replacing the deposition-inhibiting tube, so that the production efficiency by the plasma CVD apparatus can be improved.

  Further, the plasma processing apparatus according to the present invention is characterized in that the plasma is generated by electron cyclotron resonance. In this way, the damage to the sample can be reduced, so that higher quality products can be manufactured by plasma processing, and the yield can be improved. Can be.

Hereinafter, embodiments of a plasma processing apparatus according to the present invention will be described with reference to the drawings, taking an ECR sputtering apparatus as an example.
[1] Configuration of ECR Sputtering Apparatus The ECR sputtering apparatus according to the present embodiment has substantially the same configuration as the ECR sputtering apparatus according to the related art.

  FIG. 1 is a sectional view showing a configuration of the ECR sputtering apparatus according to the present embodiment. As shown in FIG. 1, the ECR sputtering apparatus 1 includes a film forming chamber 101, an exhaust port 102, a sample stage 104, a metal target 105, a plasma inlet 106, a plasma chamber 107, a waveguide 109, and a microwave introducing window 110. , A gas introduction port 111, an excitation coil 112, deposition prevention plates 113 and 114, and a deposition prevention tube 2.

The film forming chamber 101 is an airtight container for disposing a sample 103 on which a film is to be formed. The gas inside the film forming chamber 101 is sucked from the exhaust port 102 and exhausted. A sample stage 104 is provided in the film formation chamber 101, and the sample 103 is placed on the sample stage 104.
Further, a plasma introduction port 106, which is a circular opening for introducing plasma from the plasma chamber 107, is provided on a wall surface of the film formation chamber 101 in contact with the plasma chamber 107. On this wall surface, a short cylindrical metal target 105 is disposed inside the film forming chamber 101 so as to surround the plasma introduction port 106.

The metal target 105 is supported by a shield case (not shown). Note that a negative potential is applied to the metal target 105, which is lower than that of the plasma chamber 107.
The plasma chamber 107 is a cylindrical container for generating plasma by electron cyclotron resonance. On the bottom surface of the plasma chamber 107 on the film forming chamber 101 side, a circular opening is provided as a plasma introduction port 106.

On the other bottom surface of the plasma chamber 107, a rectangular opening for introducing the microwave 108 through the waveguide 109 is provided. The opening is covered with a microwave introduction window 110 made of quartz glass to keep the film forming chamber 101 and the plasma chamber 107 airtight.
In addition, an opening for introducing an argon gas is further provided on the bottom surface of the plasma chamber 107.

  The plasma chamber 107 is surrounded by an exciting coil 112 in order to generate a magnetic field in the plasma chamber 107 and generate a discharge by electron cyclotron resonance. Similarly to the plasma chamber 507 of the ECR sputtering apparatus 5, on the inner wall surface of the plasma chamber 107, deposition plates 113 and 114 for preventing adhesion of silicon oxide or the like and the deposition tube 2 are provided. ing.

  The deposition-preventing plate 113 is a disk-shaped quartz plate, and has a circular opening at a position corresponding to the plasma introduction port 106. Similarly, the deposition-preventing plate 114 is a disk-shaped quartz plate, and the micro has a rectangular opening at a position corresponding to the introduction window 110. The deposition prevention plate 114 is further provided with an opening for introducing argon gas into the plasma chamber 107.

The deposition prevention tube 2 has a cylindrical shape along the inner surface of the plasma chamber 107 and is fitted into the plasma chamber 107. The configuration of the deposition prevention tube 2 will be described later in detail.
[2] Operation of ECR Sputtering Apparatus 1 In the ECR sputtering apparatus 1, similarly to the ECR sputtering apparatus 5, a film forming process is performed as follows.

That is, first, the gas inside the film forming chamber 101 is sucked from the exhaust port 102, and the inside of the film forming chamber 101 and the plasma chamber 107 is evacuated, and moisture is removed. Next, an argon gas is introduced into the film formation chamber 101 and the plasma chamber 107.
Then, the microwave 108 is introduced from the waveguide 109 through the microwave introduction window 110, and a magnetic field is formed in the plasma chamber 107 by the excitation coil 112, thereby causing a discharge by electron cyclotron resonance. As a result, high-density plasma is generated in the plasma chamber 107, and argon ions are generated.

Since the generated argon ions have a positive charge, they are attracted to and collide with the metal target 105 to which a negative potential is applied. This collision causes silicon atoms to fly out of the metal target 105. The silicon atoms jumping out of the metal target 105 are deposited on the sample 103.
In addition, the silicon atoms jumping out of the metal target 105 may react with gas molecules in the film formation chamber 101 to generate new molecules. The molecules generated in this manner are also deposited on the sample 103. In this manner, a film formation process for forming a film on the sample 103 proceeds.

[3] Configuration of Deposition Tube 2 Next, the configuration of the deposition prevention tube 2 will be described in more detail. 2A and 2B are diagrams showing a configuration of the deposition-inhibiting tube 2, wherein FIG. 2A is an external perspective view of the deposition-inhibiting tube 2, and FIG. 2B is a plan view of the deposition-inhibiting tube 2 including a central axis thereof. FIG. 2C is a bird's-eye view in which the deposition prevention tube 2 is viewed from the film forming chamber 101 side.

Now, as shown in FIG. 2A, the protection pipe 2 is composed of three partial protection pipes: an upper pipe 21, a middle pipe 22, and a lower pipe 23. Of these three partial deposition tubes, the lower tube 23 has the largest length, which is 144 mm in the present embodiment.
On the other hand, the upper tube 21 and the middle tube 22 have shorter tube lengths of 10 mm and 12 mm, respectively. Further, as shown in FIG. 2A, the upper pipe 21 and the middle pipe 22 are provided with eight grooves 24 at equal intervals on the inner wall surface thereof in parallel with the pipe axis. The width and depth of the grooves 24 are 3 mm and 0.5 mm, respectively, and all the grooves 24 have the same dimensions.

Next, as shown in FIG. 2B, a portion where the inner diameter of the pipe is enlarged (hereinafter, referred to as an “increased inner diameter portion”) is provided near the end of the upper pipe 21 on the side of the middle pipe 22. Have been. Further, near the upper tube 21 end of the middle tube 22, there is provided a portion in which the outer diameter of the tube is reduced (hereinafter, referred to as “outer diameter reduced portion”).
The upper pipe 21 and the middle pipe 22 are connected by loosely fitting the enlarged inner diameter portion of the upper pipe 21 and the reduced outer diameter portion of the middle pipe 22.

Similarly, an enlarged inner diameter portion is provided near the lower tube 23 end of the middle tube 22, and an outer diameter reduced portion is provided near the middle tube 22 end of the lower tube 23. The middle pipe 22 and the lower pipe 23 are connected by loosely fitting them.
[4] Characteristics of Deposition Tube 2 (1) As described above, a temperature gradient is generated inside the plasma chamber 107 during the film formation process. In particular, since the temperature difference between the inside of the plasma chamber 107 and the inside of the film formation chamber 101 is large, a larger temperature gradient also occurs in the deposition-proof tube 2 in a portion near the film formation chamber 101.

Due to this temperature gradient, the degree of thermal expansion is larger in a portion of the deposition-preventing tube 2 close to the film forming chamber 101, and the degree of thermal expansion is smaller in a portion far from the film forming chamber 101.
FIG. 2B shows the situation during this time. As shown in FIG. 2B, a thermal stress 31 having a magnitude corresponding to the distance from the film forming chamber 101 acts on each partial deposition prevention tube. That is, the thermal stress increases as the distance from the film forming chamber 101 increases, and decreases as the distance from the film forming chamber 101 increases.

  To prevent such a phenomenon, the protection tube 2 according to the present embodiment is divided into the three partial protection tubes described above, and these are loosely fitted. Even if a difference occurs in the degree of thermal expansion, each partial deposition tube can freely expand. That is, since no internal stress due to thermal expansion is generated between the partial deposition tubes, thermal fatigue due to such internal stress does not occur.

Therefore, it is possible to avoid damage to the deposition prevention tube 2 due to thermal fatigue. If the protection tube 2 is not damaged, the silicon oxide attached to the protection tube 2 and the quartz pieces generated from the protection tube 2 do not scatter, so that the ECR sputtering apparatus 1 can maintain excellent film forming characteristics. .
(2) In addition, paying attention to each partial deposition tube, as described above, silicon oxide or the like is deposited on the inner surface of the partial deposition tube to form a film. This film also expands when heated by the plasma. Due to the expansion of the film, a stress 32 as shown in FIG. 2C is generated on the inner surface of the partial deposition prevention tube.

With respect to such stress 32, in the present embodiment, since the groove as described above is provided inside the partial deposition prevention tube, distortion due to the stress 32 due to expansion of the film can be released. Therefore, the deposition prevention characteristics of the ECR sputtering apparatus 1 can be maintained by preventing the deposition prevention tube 2 from being damaged.
(3) Further, since the temperature difference between the film forming chamber 101 and the plasma chamber 107 is large, the upper pipe 21 which receives a larger thermal stress is more likely to be damaged than the middle pipe 22 and the lower pipe 23. Further, for the same reason, the middle pipe 22 is more easily damaged than the lower pipe 23. On the other hand, according to the present embodiment, when the protection tube is damaged, only the damaged partial protection tube needs to be replaced.

That is, unlike the case of the above-described conventional technique, it is not necessary to replace the entire deposition-proof tube, so that the cost required for the deposition prevention measures in the ECR sputtering apparatus can be reduced.
[5] Modifications Although the invention of the present application has been described based on the embodiment, it is needless to say that the invention of the application is not limited to the above-described embodiment, and the following modification may be implemented. it can.

(1) In the above-described embodiment, the specific length of each partial protection tube constituting the protection tube 2 has been described as an example. However, it is needless to say that the present invention is not limited to this. However, as described above, the effect of the invention of the present application can be obtained as long as the protection tube is composed of a plurality of partial protection tubes.
In this case, it is preferable that the length of each partial deposition tube be determined in consideration of the temperature distribution at the time of performing the film forming process in the ECR sputtering apparatus 1. That is, it is desirable to determine the length of the tube so that the temperature difference between the portions of one partial deposition prevention tube falls within a predetermined range.

If the pipe length is determined in this manner, the thermal stress acting on the partial protection pipe can be reduced, so that the partial protection pipe can be hardly damaged by thermal fatigue. Therefore, it is possible to extend the life of the deposition prevention tube and reduce the cost related to the film forming process of the ECR sputtering apparatus 1.
(2) In the above-described embodiment, the invention of the present application has been described by taking as an example the case where the number of partial deposition prevention tubes constituting the deposition prevention tube 2 is three, but it is needless to say that the invention of the present application is not limited to this. The effect of the present invention can be obtained as long as the number of partial deposition tubes constituting one deposition tube is two or more.

In determining the number of partial deposition tubes constituting one deposition tube, the temperature distribution at the time of performing the film forming process in the ECR sputtering apparatus 1 is determined in the same manner as in determining the length of the partial deposition tube. It is preferred to take into account.
That is, when the temperature gradient along the axis of the deposition-proof tube on the inner surface of the deposition-preventing tube when performing the film-forming process in the ECR sputtering apparatus 1 is gentle, even if the number of partial deposition-proof tubes is reduced. On the contrary, when the temperature gradient is steep, it is preferable to increase the number of partial deposition tubes.

If the number of partial protection tubes is determined in this manner, the thermal stress acting on each partial protection tube can be reduced, so that the partial protection tubes can be hardly damaged by thermal fatigue. Therefore, it is possible to extend the life of the deposition prevention tube and reduce the cost related to the film forming process of the ECR sputtering apparatus 1.
(3) In the above-described embodiment, the case where eight grooves are provided on the inner surface of the partial protection tube has been described. However, it is needless to say that the present invention is not limited to this, and the inner surface of the partial protection tube. Even if the number of grooves provided is not eight, the effect of the present invention can be obtained by providing at least one groove.

  In this case, it is preferable that the number of grooves provided on the inner surface of the partial protection tube is determined according to the thickness and quality of the adhered film formed on the inner surface of the partial protection tube. This is because the magnitude of the stress applied to the partial deposition protection tube changes depending on the film thickness and film quality of the adhered film. When the stress is small, the number of grooves may be reduced, and when the stress is large, It is desirable to increase the number of grooves.

Further, in the above embodiment, the case where the groove is not provided in the lower pipe 23 has been described, but it is needless to say that the present invention is not limited to this. good.
In this case, it is desirable that the number of grooves provided on the inner surface is the same between the partial deposition tubes constituting one deposition tube, but the stress generated due to the adhered film is not In the case where the number of grooves is significantly different, the number of grooves provided may be different depending on the stress.

In the case where a plurality of grooves are provided on the inner surface of the partial protection pipe, it is preferable to provide the grooves at regular intervals around the pipe axis of the partial protection pipe. With this configuration, the stress applied to the inner surface of the partial protection tube can be averaged to suppress the maximum value of the stress, so that the partial protection tube can be hardly damaged.
(4) In the above embodiment, the inner diameter enlarged portion provided on the partial deposition protection tube on the side closer to the film formation chamber 101 is reduced to the outer diameter reduction provided on the partial deposition prevention tube on the far side from the film formation chamber 101. Although it has been described that the partial protection pipes are connected to each other by fitting the parts, it is needless to say that the present invention is not limited to this, and that the partial protection pipes are connected by a method different from the above embodiment. Is also good.

That is, contrary to the above-described embodiment, the outer diameter reduction portion provided on the partial deposition prevention tube on the side closer to the film formation chamber 101 is provided, and the outer diameter reduction portion is provided on the partial deposition prevention tube on the side far from the film formation chamber 101. An inner diameter enlarged portion may be provided, and these may be fitted together to connect the partial protection tubes.
Further, in addition to such a phased joint, the partial protection pipes may be connected to each other by oblique sliding connection, or depending on the thickness of the side wall portion of the partial protection pipe, the partial protection pipes may be connected by the core connection. They may be combined. The effect can be obtained by implementing the present invention irrespective of the method of connecting the partial deposition prevention tubes.

In consideration of the fact that a difference occurs in the degree of thermal expansion between the partial deposition tubes during the film forming process, it is preferable to provide a certain margin between the partial deposition tubes for coupling. By providing such a margin, the difference in the degree of thermal expansion can be absorbed and the thermal fatigue of the partial deposition prevention tube can be suppressed, so that the effect of the present invention can be further enhanced.
(5) In the above embodiment, the ECR sputtering apparatus is taken as an example for describing the present invention, but it goes without saying that the application of the present invention is not limited to the ECR sputtering apparatus. The effect can be obtained by applying the present invention to a high-density plasma processing apparatus.

That is, the present invention is applied to a plasma processing apparatus that performs processing by generating induction coupled plasma (ICP) or a plasma processing apparatus that performs processing by generating helicon-wave excited plasma (HWP). May be applied.
FIG. 3 is a cross-sectional view illustrating a configuration of an ICP sputtering apparatus according to the present modification. As shown in FIG. 3, in the ICP sputtering apparatus, a coil 312 is provided around a plasma chamber 307, and a high-frequency current is applied to the coil to generate inductively coupled plasma, thereby performing a sputtering process.

Also in such an ICP sputtering apparatus, breakage of the deposition prevention tube 315 can be prevented by dividing the deposition prevention tube 315 disposed inside the plasma chamber 307 according to the temperature gradient at the time of plasma generation. Thus, the effects of the present invention can be obtained.
The present invention is particularly effective when the plasma density reaches 10 ¹⁰ ions / cm ³ or more irrespective of the plasma generation method, and has effects such as extending the life of the plasma processing apparatus.

(6) In the above embodiment, an ECR sputtering apparatus was taken as an example for describing the present invention, but it goes without saying that the application of the present invention is not limited to the ECR sputtering apparatus. The effects can be obtained by applying the present invention to a plasma processing apparatus.
FIG. 4 is a cross-sectional view illustrating the configuration of a reactive ion beam etching (RIBE) device (hereinafter, referred to as a “RIBE device”) including a deposition-preventing tube according to a modification of the present invention. .

As shown in FIG. 4, the RIBE apparatus 4 according to the present modification includes a sample (wafer) 401, a sample stage 402, a sample chamber 403, an ion extraction electrode 404, an excitation coil 405, a microwave introduction window 406, a waveguide 407, a plasma chamber 410, a deposition prevention plate 411, and a deposition prevention tube 412.
In the RIBE apparatus 4, after the inside of the sample chamber 403 is evacuated, the microwave 408 is introduced from the waveguide 407 through the microwave introduction window 406, and the source gas 409 is introduced into the plasma chamber 410. Then, the RIBE device 4 forms a magnetic field in the plasma chamber 410 by the excitation coil 405, and generates a discharge by electron cyclotron resonance. Then, high-density plasma is generated.

  Then, a negative potential is applied to the ion extraction electrode 404 to extract reactive element ions 413 from the plasma. Here, the sample stage 402 is an electrode on a flat plate, and when a high-frequency voltage is applied to the sample stage 402, a DC electric field is generated. As a result, the reactive element ions 413 are vertically incident on the wafer 401, and anisotropic etching is performed.

Since it is necessary to prevent unnecessary substances from adhering to the inner wall of the sample chamber 403 when performing the etching in this manner, a circular deposition plate 411 and a cylindrical deposition tube are provided inside the sample chamber 403. 412 are installed.
In the RIBE apparatus, similarly to the ECR sputtering apparatus, since a large temperature difference occurs between the sample chamber and the plasma chamber, there is a problem that the deposition prevention tube is damaged by thermal fatigue.

On the other hand, in the RIBE device 4 according to the present modification, the deposition tube 412 is divided into a plurality of partial deposition tubes according to the temperature distribution during the etching process, similarly to the deposition tube 2. Therefore, the damage as described above can be avoided. Therefore, since the frequency of replacing the deposition-inhibiting member can be reduced, various costs related to the etching process can be reduced.
The present invention can be applied to an ECR plasma CVD (Chemical Vapor Deposition) apparatus to provide the same effects as described above. FIG. 5 is a cross-sectional view illustrating the configuration of an ECR plasma CVD apparatus according to the present modification.

As shown in FIG. 5, the ECR plasma CVD apparatus 5 includes a sample chamber 501, a sample table 502, a wafer 503, an excitation coil 504, a plasma chamber 505, a microwave introduction window 506, a waveguide 507, a deposition plate 510, 512 and a deposition prevention tube 511.
The ECR plasma CVD apparatus 5 first evacuates unnecessary gas inside the sample chamber 501 and the plasma chamber by a vacuum pump. Then, a microwave 508 having a frequency of 2.45 GHz is introduced from the magnetron into the plasma chamber 505 through the waveguide 507 and the microwave introduction window 506. Further, nitrogen gas (N ₂ ) or the like is introduced into the plasma chamber 505 as a source gas.

In this state, when a magnetic field (875 G) is applied to the plasma chamber 505 using the excitation coil 504, high-density plasma is generated by electron cyclotron resonance. The active gas molecules thus obtained are guided to the sample chamber 501 and reacted with the silane gas (SiH ₄ ) 513 separately introduced into the sample chamber 505 to deposit a Si ₃ N ₄ film on the wafer 503.
Also in this case, in order to prevent unnecessary substances from adhering to the inner wall of the sample chamber 501 to form a film, deposition plates 510 and 512 and a deposition tube 511 are provided in the sample chamber 501. . In order to prevent the deposition tube 511 from being damaged due to the temperature difference between the sample chamber 501 and the plasma chamber 505, the deposition tube 511 according to the present modified example has a temperature distribution during the ECR plasma CVD process. Is divided into a plurality of partial deposition prevention tubes.

By doing so, the frequency of replacing the deposition-inhibiting member can be reduced, so that various costs associated with the ECR plasma CVD processing can be reduced.
It is needless to say that the effects of the present invention can also be obtained when the above-described etching process or CVD process is performed using plasma generated by a method other than ECR such as ICP or HWP.

(7) In the above-described embodiment and modified examples, the case where the deposition tube or the deposition plate is in contact with the inner wall of the plasma chamber or the sample chamber has been described as an example. However, the present invention is not limited to this. Needless to say, the following may be used instead of these.
That is, as described above, the deposition tube and the deposition plate are provided to prevent unnecessary substances from adhering to the inner walls of the plasma chamber and the sample chamber, and thus achieve the above object. For example, the outer diameter of the deposition prevention tube may be smaller than the inner diameter of the plasma chamber or the sample chamber. Further, in this case, the area of the protection plate may be smaller than the area of the inner wall surface to which the protection plate is attached.

  The size and shape of the deposition tube and the deposition plate may be determined according to the size and shape of the plasma chamber or the sample chamber to which they are attached. Irrespective of the size and shape of the protection tube, breakage of the protection tube can be suppressed by dividing the protection tube into a plurality. Therefore, it is possible to reduce the frequency of replacement of the deposition-inhibiting tube and reduce the running cost of the plasma processing apparatus.

  The plasma processing apparatus according to the present invention relates to plasma processing by extending the life of a deposition-preventing member that prevents silicon oxide or the like from adhering inside the plasma processing apparatus when performing processing such as thin film formation using plasma. This is useful as a technique for reducing costs.

It is a sectional view showing the composition of the ECR sputtering device concerning an embodiment of the invention of this application. FIG. 2A is a diagram showing a configuration of a deposition-proof tube 2 according to an embodiment of the present invention, in which FIG. 2A is an external perspective view of the deposition-proof tube 2, and FIG. 2 (c) is a bird's-eye view of the deposition prevention tube 2 from the film forming chamber 101 side. It is sectional drawing which illustrates the structure of the ICP sputtering apparatus provided with the deposition prevention tube which concerns on the modification of this invention. It is sectional drawing which illustrates the structure of the reactive ion beam etching apparatus provided with the deposition prevention tube which concerns on the modification of this invention. FIG. 9 is a cross-sectional view illustrating a configuration of an ECR plasma CVD apparatus according to a modification of the present invention. It is a sectional view which illustrates the composition of the ECR sputtering device concerning a conventional technology.

Explanation of reference numerals

1, 6 ...... ECR sputtering equipment 2, 315, 412, 511, 620 ...... Deposition tube 4 ... ............ …………………………………………………………………………………………………………………………………………………… ECR plasma CVD apparatus 21 ……………………… …………………………………………………………………………………………………… Middle pipe 23 ………………………………………………………………………………… 24 ……………………………………………………………………………………… Thermal stress 32 …………………… …………… Stress 101, 301, 601 …………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………… 503, 603 ... sample (wafer)
104, 304, 402, 502, 604 sample table 105, 305, 605 metal targets 106, 306, 606 plasma inlets 107, 307, 410 , 505, 607: plasma chambers 108, 308, 408, 508, 608: microwaves 109, 309, 407, 507, 609: waveguides 110, 310, 406, 506, 610: microwave introduction windows 111, 311; 611: Gas inlets 112, 405, 504, 612 ... Excitation coils 113, 114, 313, 314, 411: Protective plate 312 ... ............ ……………………………………………………………………………… High-frequency power supply for bias 317 ……………………………… Power supply 403, 01 ……………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………… …………………………………………………………………………………………………………………………………………. ……………………… Silane gas

Claims (16)

A plasma chamber for generating high-density plasma;
A sample chamber that is in communication with the plasma chamber, and that holds a sample to be processed by the plasma;
A deposition prevention tube for preventing a product of the plasma processing from adhering to an inner wall of the plasma chamber,
The plasma processing apparatus according to claim 1, wherein the deposition prevention pipe is divided into a plurality of pieces according to a temperature distribution at the time of the plasma generation. The plasma chamber has a cylindrical shape,
2. The plasma processing apparatus according to claim 1, wherein the attachment tube has a cylindrical shape, is inserted into the plasma chamber, and is divided in a tube axis direction. 3. 3. The method according to claim 2, wherein the deposition tube is divided such that a portion having a larger temperature gradient during the plasma generation has a smaller tube length, and a portion having a smaller temperature gradient has a larger tube length. 4. The plasma processing apparatus according to the above. 2. The plasma processing apparatus according to claim 1, wherein a groove parallel to the pipe axis is provided on an inner wall surface of the deposition prevention pipe. The deposition tube is provided with a plurality of grooves,
The plasma processing apparatus according to claim 4, wherein the plurality of grooves are provided at equal intervals around a pipe axis of the deposition-preventing pipe. The plasma processing apparatus according to claim 1, wherein the deposition prevention tube is made of quartz. The plasma processing apparatus according to claim 1, wherein the sample is subjected to a sputtering process using the plasma. A plasma chamber for generating high-density plasma;
A sample chamber that is in communication with the plasma chamber, and that holds a sample to be processed by the plasma;
A deposition prevention tube for preventing a product of the plasma processing from adhering to an inner wall of the sample chamber,
The plasma processing apparatus, wherein the deposition tube is divided into a plurality of pieces according to a temperature distribution at the time of generating the plasma. The sample chamber has a cylindrical shape,
9. The plasma processing apparatus according to claim 8, wherein the attachment tube has a cylindrical shape, is fitted into the sample chamber, and is divided in a tube axis direction. 10. The protection tube according to claim 9, wherein a portion having a larger temperature gradient during the generation of the plasma has a smaller tube length, and a portion having a smaller temperature gradient has a larger tube length. The plasma processing apparatus according to the above. 9. The plasma processing apparatus according to claim 8, wherein a groove parallel to the tube axis is provided on an inner wall surface of the deposition-proof tube. The deposition tube is provided with a plurality of grooves,
12. The plasma processing apparatus according to claim 11, wherein the plurality of grooves are provided at equal intervals around a pipe axis of the deposition prevention pipe. 9. The plasma processing apparatus according to claim 8, wherein the deposition prevention tube is made of quartz. 9. The plasma processing apparatus according to claim 8, wherein the sample is subjected to an etching process using the plasma. The plasma processing apparatus according to claim 8, wherein the sample is subjected to a CVD process using the plasma. The plasma processing apparatus according to claim 1, wherein the plasma is generated by electron cyclotron resonance.

Images